Scavenger receptors and β-glucan receptors participate in the recognition of yeasts by murine macrophages

Objectives: Numerous receptors have been implicated in recognition of pathogenic fungi by macrophages, including the $\beta$-glucan receptor dectin-1. The role of scavenger receptors (SRs) in anti-fungal immunity is not well characterized. Methods: We studied uptake of unopsonized Saccharomycetes cerevisiae (zymosan) and live Candida albicans yeasts as well as zymosan-stimulated $H_2O_2$ production in J774 macrophage-like cells and peritoneal exudate macrophages (PEMs). The role of different receptors was assessed with the use of competitive ligands, transfected cells and receptor-deficient macrophages. Results: The uptake of zymosan by untreated J774 cells was mediated approximately half by SRs and half by a $\beta$-glucan receptor which was distinct from dectin-1 and not linked to stimulation of $H_2O_2$ production. Ligands of $\beta$-glucan receptors and of SRs also inhibited uptake of C. albicans by macrophages (J774 cells and PEMs). In macrophages pretreated with a CpG motif-containing oligodeoxynucleotide (CpG-ODN) the relative contribution of SRs to yeast uptake increased and that of $\beta$-glucan receptors decreased. Whereas the class A SR MARCO participated in the uptake of both zymosan and C. albicans by CpG-ODN-pretreated, but not untreated macrophages, the related receptor SR-A/CD204 was involved in the uptake of zymosan, but not of C. albicans. The reduction of zymosan-stimulated $H_2O_2$ production observed in DS-pretreated J774 cells and in class A SRs-deficient PEMs suggest that class A SRs mediate part of this process. Conclusions: Our results revealed that SRs belong to a redundant system of receptors for yeasts. Binding of yeasts to different receptors in resting versus CpG-ODN-pre-exposed macrophages may differentially affect polarization of adaptive immune responses

CHOOSE: Towards a metamodel for enterprise architecture in small and medium-sized enterprises

Enterprise architecture (EA) is a coherent whole of principles, methods, and models that are used in the design and realization of an enterprise's organizational structure, business processes, information systems, and infrastructure. Recent research indicates the need for EA in small and medium-sized enterprises (SMEs), important drivers of economy, as they struggle with problems related to a lack of structure and overview of their business. However, existing EA frameworks are perceived as too complex and no EA approach adapted to an SME context exists. Therefore, this paper presents the CHOOSE metamodel for EA in SMEs that is developed and evaluated during action research in a Belgian SME. This metamodel is based on the essentials of EA frameworks and is kept simple to be usable in an SME context. The final CHOOSE metamodel includes only four essential concepts (goal, actor, operation, object), one for each most frequently used EA focus. An extract from the CHOOSE model from the Belgian SME is presented as an example. Finally, the CHOOSE metamodel is evaluated according to the EA essentials and the requirements for EA in an SME context

Enterprise architecture for small and medium-sized enterprises: a starting point for bringing EA to SMEs, based on adoption models

Enterprise architecture (EA) is used as a holistic approach to keep things aligned in a company. Some emphasize the use of EA to align IT with the business, others see it broader and use it to also keep the processes aligned with the strategy. EA has gained importance in larger companies. Although a lot of research is being done on EA, still hardly anything is known about its use in the context of a small and medium-sized enterprise (SME). Although EA can offer a lot of benefits to SMEs, still hardly any SME uses EA. In this paper, the authors analyze both SMEs and EA techniques and investigate the adoption of EA in SMEs. At the end of the chapter, some guidelines for EA technique developers are proposed